Telephone-transmitter.



PATENTED AUG. 16, 1904.

* 0. W. HARPER.

TELEPHONE TRANSMITTER.

APPLICATION FILED SEPT. 12, 1902.

N0 MODEL.

CHARLES W. HARPER, OF

Patented August 16, 1904.

PATENT OFFICE.

MALDEN, MASSACHUSETTS.

TELEPHONE-TRANSMlTTER.

SPECIFICATION forming part of Letters Patent No. 767,753, dated A g 16, 1904.

I Application filed September 12, 1902. Serial No. 123,060. (No model.)

lbv ctZZ. 1071,0712, it may concern.-

Be it known that l, CHARLEs 1V. HARPER, a citizen of the United States, and a resident of Malden, in the county of Middlesex and State of Massachusetts, have invented new and useful Improvements in Telephone-Transmitters,

of which the following is a specification.

Figure 1 is a side view of my improved transmitter, the cover of the casing being removed to expose the interior. Fig. 2 is a section on line 2 2 of Fig. 1. Fig. 3 is a detail of some of the parts of the transmitter shown in Figs. 1 and 2. Fig. 1 shows a complete telephone system embodying one form of my invention applied to the person of an individual.

My invention relates to telephone-transmitters, and has for its object to improve the construction of the same to the end that better results may be secured in the transmission and reproduction of sound or speech than has been possible heretofore.

Particularly my invention has for its object to provide an improved telephone-transmitter especially adapted for use by individuals more or less deaf and to be carried upon the person of such individuals without inconvenience to them.

The novel features of my invention are hereinafter fully set forth in the following description, and particularly pointed out and clearly defined in the claims at the close thereof.

Having reference to the drawings, T represents the transmitter, the diaphragm 1 of which is made, preferably, of aluminium and has fastened upon one face a disk 2, of carbon, which constitutes the movable electrode. The edge of diaphragm 1 is covered by a band 3, of rubber or other cushioning and insulating material, and this edge is clamped between a seat 4, provided on a frame 5, and a clamping member 6. The clamping member 6 is exteriorly screw-threaded to engage threads upon the interior of frame 5, so that it may be caused to clamp the diaphragm 1 more or less firmly on its seat. The clamping member 6 is made with a cross-bar 61, in which is mounted a screw 7, locked in adl justed position by a set-screw 71. At its inner end screw 7 is reduced and engages an in- -teriorly-screw-threaded socket provided on a holder 8, in which socket-screw 8 is locked by a set-screw 9. Holder 8 carries the fixed electrode 10 and also a ring 11, of cotton, felt, or

of carbon-granules 12. Upon cross-bar 61 is fastened a block 13, of insulating material, which carries a resilient contact member 14, whose end bears on electrode 2. The degree of pressure of contact member 14 on electrode 2 is regulated by a screw 15, and this contact member 14: serves not only as an electrical connection, but also to control and regulate the action of diaphragm ,1 to some extent.

The frame 5 is made in the form of a ring, and its exterior is screw-threaded to engage screw-threads provided on the interior of a casing 16, of hard rubber or other suitable material, which is provided with a removable back 161, permitting access to the interior. Through this casing extends a sleeve 17, which at its inner end is connected with frame 5. This sleeve serves as a socket for a removable plug 18, fast to a switch-block 19 and connected by wire 181 with one pole of a battery B. Another sleeve 20 extends through casing 16 and is connected by wire 21 with member 14. This sleeve 20 is insulated from frame 5 by a sleeve 22. Sleeve 20 serves as a socket for a plug 23, fast on switch-block 19 and connected by wire 231 with the other pole of battery B through the receiver R.

Socket 17 and plug 18 are made larger than socket 20 and plug 23, so as to make it impossible to connect the wrong pole of battery B with either socket 17 or 20. The plugs 18 and 23 are split longitudinally and sprung so as to frictionally engage the sockets when forced into them.

The front wall 162 of casing 16 is provided with a centrally-arranged group of perforations 163, and it also is provided upon its interior face with an annular groove 164, which latter I find greatly improves the acoustic properties of the chamber in front of the diaphragm 1. This chamber is also greatly imother suitable material, within which is a body proved in this respect by making its periphery beveled, as at By my invention a very simple and effective tclephone-transmitter is provided which can be worn upon the person without inconven presented by the 0rdinaryspeakingtelephone,

as for practical use it is desirable, in the first instance, that the speaker may be at any rea sonable distance from the transmitter, at such a distance, in fact, as in ordinary conversation persons may naturally be placed, while in the ordinary telephone-transmitter the speaker places his lips close to the transinitter.

It will be recognized by those skilled in the art that the ordinary transmitter employed in such a manner as I have described and for such a purpose would be ineffective, while by my improved transmitter the sounds received are owing to its peculiar arrangement and adjustment transmitted in full volume to the receiver and to the ear of the user.

My improved transmitter is designed to be adjusted to suit the peculiar needs of the individual for whose use it is designed. The cars of deaf persons vary from a very slight defect to a deafness which notes only very great noises, and for this reason it is requisite and necessary that the instrument be adjusted to the individual for reasons which will appear later in this specification. l have found that the loudness or volume of sound which the transmitter causes the receiver to produce is to a large degree proportionate to the pressure of the annular knife-edges of the clamping members on the diaphragm. It is a fact, however, that while an increase of pressure on the diaphragm will cause an increase in the volume of sound produced at the receiver, yet this increase is not accomplished without detracting slightly from distinctness of articulation. This, however, is not serious and in a measure corrects itself, since the ear of the user soon learns to translate without effort and automatically the sounds thus presented to the ear, although fuller and less articulate than the sounds normally heard. I have, however, succeeded in minimizing this result of slightly-defective articulation by the use of the finger 1 by the regulation of which a clear articulation of the instrument may be in a very large part restored without detracting in any measurable degree from the volume of sound gained by the use of pressure around the periphery of the diaphragm. Thus by means of theclamping member 6 and spring-finger 14: the instrument may be adjusted to suit any ear and when properly adjusted will give a large volume of sound and very good articulation.

By providing the seat for the diaphragm on a metal frame which carries all the parts of the instrument those parts may be quickly set up and perfectly and permanently adjusted before the frame isput in the casing, which is a desirable feature. Also as the frame and clam 'iing member are both preferably made of the same material there is no unequal expansion between those parts to destroy the adjustment thereof.

By mounting the small carbon disk 2 on diaphragm 1 instead of providing a separate carbon diaphragm, as heretofore, the sensitiveness of the instrument is increased to a marked degree, while the movements of the diaphragm cause finger 14 to rub on disk 2 and to thereby maintain a clean and perfect contact between the twoparts.

What 1 claim is- 1. In a transmitter in combination, a frame provided with an annular knife-edge; aclamping member adjustably mountedon said frame and provided with an annular knife-edge of the same diameter as the knife-edge on the frame and directly opposed thereto; and a diaphragm clamped near its edge between the annular knife-edge on the frame and the annular knife-edge on the clamping member.

2. The above-described transmitter comprising a frame provided with an annular knife-edge; a clamping member adjustably mounted on said frame and provided with an annular knife-edge of the same diameter as the knife-edge on the frame and directly opposed thereto; a diaphragm clamped near its edge between the annular knife-edge on the frame and the annular knife-edge on the clamping member; an electrode controlled by the diaphragn'l; a fixed electrode; and an adjustable resilient finger acting on the diaphragm.

3. The above-described transmitter comprising a metal frame provided with an annular knife-edge; a metal clamping member adjustably mounted on said frame and provided with an annular knife-edge of the same diameter as the knife-edge on the frame, and directly opposed thereto; a metal diaphragm clamped near its edge between the annular knife-edge on the frame and theannular knifeedge on the clamping member; insulation between the two knife-edges and the diaphragm; an electrode controlled by the diaphragm; a fixed electrode and an adjustable resilient finger resting against said diaphragm.

f. The above-described transmitter comprising an interiorly-threaded casing; an exteriorly and interiorly threaded ring screwed into the casing provided with an annular knifeedge diaphragm-seat; an exteriorly-threaded clamping-ring provided with an annular knifeedge of the same diameter as the first knifeedge and directly opposed thereto; a diaphragm clamped near its edge between the two knife-edges; an electrode controlled by the diaphragm, and a fixed electrode.

5. The improved transmitter above described,comprising an interiorly-threaded casing; an interiorly and exteriorly threaded ring screwed into said casing, said ring beingmade with an inwardly-projecting diaphragm-seat; an exteriorly-threaded clam pin g-rin g screwed into the first-mentioned ring; a diaphragm clamped near its edge between the diaphragmseat and said clamping-ring; an electrode connected with the diaphragm, and an adjustable fixed electrode I mounted centrally on the clamping-ring.

6. The improved transmitter above described comprising an interiorly-thread ed casing; an interiorly and exteriorly threaded ring screwed into said casing, said ringbeingmade with an inwardly-projecting diaphragm-seat; an eXteriorly-threaded clamping-ring screwed into the first-mentioned ring; a diaphragm clamped near its edge betweenthe diaphragmseat and said clamping-ring; an electrode mounted on the diaphragm; aresilient finger mounted on but insulated from the clampingring; said finger arranged to bear upon said electrode, and a fixed electrode mounted on the clamping-ring. I

7 The improved transmitter above described comprising an interiorly-threaded casing made of non-conducting material, an interiorly and exteriorly threaded ring screwed into said casing said ring being made with an inwardly-projecting diaphragm-seat; an exteriorly-threaded clamping-ring screwed into the first-mentioned ring, said clamping-ring being made with a cross-bar; a diaphragm clamped near its edge between the diaphragmseat and said clamping-ring; an electrode mounted on the diaphragm; a resilient finger mounted on but insulated from the clamping ring, said finger being arranged to bear upon said electrode; means to regulate the pressure of said finger on said electrode and a fixed electrode mounted on the cross-bar of the clamping-ring.

8. The improved transmitter above described comprising an interiorly-threaded casing made of non-conducting material; an interiorly and exteriorly threaded ring screwed into said casing, said ring being made with an inwardly-projecting diaphragm-seat; an exteriorly-threaded clamping-ring screwed into the first-mentioned ring, said clampingring being made witha cross-bar; ametaldiaphragm clamped near its edge between the diaphragm-seat and said clamping-ring; a ring of insulating material between the border of the diaphragm and the two rings; an electrode mounted on the diaphragm; a resilient finger mounted on butinsulated from the clampingring, said finger being arranged to bear upon said electrode; means to regulate the pressure of said finger on said electrode; a fixed electrode mounted on the clamping-ring, and a pair of terminals one of which is connected, with said finger and the other with one of said rings.

9. The improved transmitter above described, comprising an interiorly-threaded casing; an exteriorly and interiorly threaded ring screwed into said casing, said ring being made with an inwardly-projecting knife-edge diaphragm seat; an exteriorly threaded clampingring screwed into the firstmen tioned ring, said clamping ring being made with a cross-bar and with an annular knifeedge opposed to the knife-edge diaphragm-seat on the outer ring; a diaphragmclamped near its edge between the diaphragm-seat and the annular knife-edge on the clamping-ring; an electrode mounted on the diaphragm; a resilient finger mounted on but insulated from the clamping-ring; said finger being arranged to bear upon said electrode; means to regulate the pressure of said finger on said electrode; a fixed electrode mounted on the cross-bar of the clamping-ring, and means to adjust the fixed electrode on the cross-bar of the clam ping-ring toward and from the electrode on the diaphragm.

10. The improved transmitter above described comprising an interiorly threaded casing; an exteriorly and interiorly threaded ring screwed into said casing, said ring being made with an inwardly-projecting diaphragmseat; an exteriorlythreaded clamping-ring screwed into the first-mentioned ring, said clamping-ring being made with a cross-bar; a diaphragm clamped near its edge between the diaphragm seat and the clamping ring; an electrode mounted on the diaphragm; a resilient finger mounted on but insulated from the clamping-ring, said finger being arranged to bear upon said electrode; means to regulate the pressure of said finger on said electrode; a screw mounted on said cross bar with its axis normal to the plane of the diaphragm; a holderdetachably fixed to the end of said screw adjacent the diaphragm; and a fixed electrode supported by said holder.

11.- The improved transmitter above described comprising an interiorly threaded casing; an exteriorly and interiorly threaded ring screwed into said casing; said ring being made with an inwardly-projectingdiaphragmseat; an exteriorly-threaded clamping-ring, said clamping-ring being made with a crossbar a diaphragm clamped near its edge between the diaphragm-seat and the clampingring; an electrode mounted on the diaphragm; a resilient finger mounted on but insulated from the clamping-ring; said finger being arranged to bear upon said electrode; means to regulate the pressure of said finger on said electrode; a screw mounted on said cross-bar with its axis normal to the plane of the diaphragm; means to lock said screw in adjusted position; a holder detachably fixed to the end of said screw between the cross-bar and the electrode on the diaphragm; and a fixed electrode supported by said holder.

12. The improved transmitter above described comprising an interiorly-threaded casing; an exteriorly and interiorly threaded metal ring screwed into said casing, said ring being made with an inwardly-projecting diaphragm-seat; an exteriorly-threaded metal clamping-ring screwed into the first-mentioned ring, said clamping-ring being made with a cross-bar and with an annular knifeedge of the same diameter as the diaphragmseat on the outer ring; a metal diaphragm clamped near its edge between the diaphragmseat and the annular knife-edge on the clamping-ring; a cushioning-ring of non-conducting material insulating the diaphragm from the two rings; an electrode mounted on the diaphragm; a resilient finger mounted on but insulated from the clamping-ring; said finger being arranged to bear upon said electrode; means to regulate the pressure of said finger on said electrode, a screw mounted in said cross-bar with its axis normal to the plane of the diaphragm; means to lock said screw in adjusted position; a holder detachably fixed to the end of said screw between the crossbar and the electrode on the diaphragm; a fixed electrode supported by said holder; a pair of terminals extending through the wall of said casing, one of said terminals being connected with the resilient finger and the other with one of said rings.

13. The improved transmitter above described comprising a closed interiorly-tiiread ed casing of non-conducting material, made with an opening in its front wall and equipped with means for attaching it to a person; an exteriorly and interiorly threaded metal ring screwed into said casing, said ring being made with an inwardly-projecting reentrant knifeedge diaphragm-seat; an eXteriorly-threaded metal clamping-ring screwed into the firstmentioned ring, said clamping-ring being made with a cross-bar and with an annular knife-edge of the same diameter as the knifeedge on the outer ring; a metal diaphragm clamped near its edge between the two knifeedges; a cushioning-ring of non-conducting material insulating the diaphragm from the two rings; an electrode mounted on the diaphragm; a resilient finger mounted on but insulated from the cross-bar of theclampingring, said finger being arranged to bear upon said electrode; means to regulate the pressure of said linger on said electrode; a screw mounted in said cross-bar with its axis normal to the plane of the diaphragm; means to lock said screw in adjusted position; a holder detachably fixed to the end of said screw between the crossbar and the electrode on the diaphragm; a fixed electrode supported by said holder; a pair of terminals extending through the wall of said casing; one of said terminals being connected with the resilient finger and the other with one of said rings; and a disk of non-conducting material threaded on its periphery and screwed into said casing behind the two rings. I

Signed by me at Boston, Massachusetts, this 8th day of September, 1902.

CHARLES W. HARPER. Witnesses:

J OSEPH T. BRENNAN, GRACE E. GIBBoNs. 

